Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
tinh hai » tinh thai, tinh chat, trinh han
hanh may » hanh ma, hanh mau, hanh ngay
so sach » so sanh, bo sach, co sach
hai cua » thai cua, dai cua, hoi cua
va tinh » may tinh
cam duc » cam xuc, cao duc, pham duc
hieu ve » hieu va
sach tu » sach thu, cach tu, sach ty
hanh xa » hanh va, hanh ma, hanh xu
cua tre » cua te, cuu tre, cua triet

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: so sach tu ((hanh xa) or (hanh may)) hoi. ((hieu ve) OR (hieu van)) cam duc va tinh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach tu ((hanh xa) OR (hanh may)) hoi. ((hieu ve) OR (hieu van)) cam duc va tinh hai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach tu ((hanh xa) or (hanh may)) hoi. ((hieu ve) OR (hieu van)) cam duc va tinh hai cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach tu ((hanh xa) or (hanh may)) hoi. ((hieu ve) OR (hieu van)) cam duc va tinh hai cua tre*.